The invention relates to a focal plane shutter camera having an electromagnetic diaphragm mechanism.
A camera employing an electrically operated focal plane shutter, being controlled by photometry measuring light reflected by the shutter blind and/or the film, such as a single lens reflex camera of focal plane shutter type is capable of an automatic photographing operation with a preset diaphragm aperture in which the diaphragm aperture is previously selected and the exposure period is automatically determined, and a manual operation in which both the diaphragm aperture and the exposure period are manually determined. However, such camera is incapable of an automatic photographing with a preset exposure period in which the exposure period is preset and the diaphragm aperture is automatically determined or an automatic, programmed photographing operation in which both the diaphragm aperture and the exposure period are automatically determined.
However, it will be appreciated that it is convenient to provide a single camera which permits a selection among these various photographing modes to enable a greater flexibility in the photographing operation. However, the resulting arrangement will require at least two light receiving elements for the purpose of photometry, with a consequent complicated circuit arrangement to cause an increase in cost, which prevented its practical implementation.